This invention pertains to hermetically sealed, positive displacement compressors for compressing refrigerant in refrigeration systems such as air conditioners, refrigerators and the like. In particular, the invention describes a rotary compressor mechanism, having a discharge chamber and a sump disposed therein and being of the type which includes a cylinder block having a cylindrical cavity, a bearing assembly and a motor assembly driving a roller piston disposed in the cylindrical cavity. More particularly, the cylinder block includes a vane slot, partially defined by a pair of vane slot sidewalls, extending completely axially through the cylinder block to accommodate a reciprocating vane therein and the vane being urged against a roller piston.
Rotary compressors are well known in the art, as exemplified by U.S. Pat. No. 4,889,475 which is assigned to assignee of the present application. Generally, the tolerances between the reciprocating vane and the slot sidewalls defining the vane slot of the cylinder block must be tightly controlled in order to optimize compressor efficiency. Proper vane clearances are necessary to allow free reciprocation of the vane in its slot and to allow sealing against discharge pressure gas blow-by therebetween. Maintaining these clearances in previous compressors often requires precision vane and/or slot machining, or select fitting of the individual vanes and cylinder blocks. A disadvantage arising from precision machining of the slot and/or vane is the associated cost of precision machining a pair of sidewalls defining the vane slot and vane. Always existent with precision machining is the immense cost associated with the act of "scrapping a part" when one of the final operations is spoiled due to a myriad of possible and easily made mistakes. A structure for easily providing a seal between the vane and their slot without resorting to costly and time consuming machining operations or select fitting is needed.
Generally, rotary compressor construction includes laboriously preparing the vane and vane slot for an introduction of the vane into the vane slot to provide a sealable fit therebetween when a lubricant is introduced therein. A disadvantage, already mentioned hereinabove, is that laboriously preparing components, through precision machining and the like, has an increased cost associated therewith. Components, such as the vane and vane slot satisfactorily sealing during operation, without the heretofore required precise machining of the vane and vane slot would be highly desirous.
Generally, rotary compressors heretofore disclosed include porting or journaling such that through suction of refrigerant gas, liquid lubricant in one portion of a compressor housing may be transferred to the cylinder block to fill the clearance between the vane and vane slot to provide a positive seal. A disadvantage of this type of lubrication is that liquid lubricant quantities vary and depend on the suction created by the compressor. Moreover, the scant amount of liquid lubricant "coating" the clearance between the vane and vane slot often acts to lubricate the clearance rather than seal it. A clearance which is sealed, and additionally lubricated, rather than merely being lubricated is highly desired.